Since that time nine novas have appeared, which have attained naked-eye visibility; and in recent years a number of very faint objects of the same class have been detected.
As they watched, the figures in the dusty heat waves finally became recognizable as cavalry - even to the naked eye.
Few persons can see with the naked eye - much less measure - more than six stars of the Pleiades, although all the stars measured by Maestlin have been seen with the naked eye by a few individuals of exceptional powers of eyesight.
These consist of enormous cells with nuclei so large as to be in some cases just visible to the naked eye.
A lenticel appears to the naked eye as a rounded or elongated scar, often forming a distinct prominence on the surface of the organ.